This part of ISO 19901 specifies requirements for controlling the weight and centre of gravity (CoG) by means of mass management during the engineering and construction of structures for the offshore environment. The provisions are applicable to offshore projects that include structures of all types (fixed and floating) and materials. These structures can be complete new installations or the modifications to existing installations. Maintaining the weight control of existing installations is not part of the main body of this part of ISO 19901, but some guidance on this is included in the Annex G.This part of ISO 19901:— specifies quality requirements for reporting of weights and centres of gravity;— specifies requirements for weight reporting;— provides a basis for overall project weight reports or management reports for all weight control classes;— specifies requirements for weight and load budgets;— specifies the methods and requirements for the weighing and the determination of weight and CoG of major assemblies;— specifies requirements for weight information from suppliers, including weighing of equipment and bulk materials for offshore installations.It can be used:— as a basis for planning, evaluating and presenting the client’s, contractor’s or fabricator’s weight management and reporting system;— as a means of refining the structural analysis or model;— as a contract reference between client, contractor and suppliers;— as a basis for costing, scheduling or determining suitable fabrication method(s) or location(s).